CVE-2026-109251 (CVSS 5.3)

Description

FreeRDP before 3.32.0 stores the server-supplied signed MS-RDPEGT geometry origin unchecked in an unsigned video surface coordinate, so the blit clamp in gdiVideoShowSurface() wraps in 32-bit arithmetic and is skipped. A malicious RDP server can send a negative topLevelLeft to clients connecting with /video, causing an out-of-bounds write of decoded H.264 picture data or a client abort.

Is your site exposed to CVE-2026-109251?

Run a free security scan — no signup, results in seconds.

CVSS v3.1 Score

5.3

MEDIUM

CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:N/A:H

EPSS — Exploit Prediction

0.0024

Probability of exploitation

0.14%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-129 CWE-129

References

Other References

https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-grvc-qhhp-7h6m https://www.vulncheck.com/advisories/freerdp-before-3.32.0-out-of-bounds-write-via-ms-rdpegt-video-geometry https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-grvc-qhhp-7h6m

Frequently Asked Questions

What is CVE-2026-109251? +

FreeRDP before 3.32.0 stores the server-supplied signed MS-RDPEGT geometry origin unchecked in an unsigned video surface coordinate, so the blit clamp in gdiVideoShowSurface() wraps in 32-bit arithmetic and is skipped. A malicious RDP server can send a negative topLevelLeft to clients connecting with /video, causing an out-of-bounds write of decoded H.264 picture data or a client abort. It has a CVSS v3.1 base score of 5.3 (MEDIUM).

How severe is CVE-2026-109251? +

CVE-2026-109251 has a CVSS v3.1 score of 5.3 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0024, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-109251? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

Related Vulnerabilities

CVE-2025-0657

A weakness in Automated Logic and Carrier i-Vu Gen5 router on driver version drv_gen5_106-01-2380, allows malformed packets to be sent …

CVE-2025-66559

Taiko Alethia is an Ethereum-equivalent, permissionless, based rollup designed to scale Ethereum without compromising its fundamental properties. In 2.3.1 and …

CVE-2023-31309

Improper validation in Power Management Firmware (PMFW) may allow an attacker with privileges to pass malformed workload arguments when exporting …

CVE-2026-19318

A stack-based buffer overflow vulnerability in the WatchGuard Fireware OS iked process allows a remote unauthenticated attacker to execute arbitrary …

CVE-2026-65652

github.com/temporalio/tchannel-go did not validate the one-byte checksum-type field in inbound TChannel call frames. A network peer that can reach a …

CVE-2026-93322

A malicious frontend can submit an LLB definition that causes buildkitd to panic and terminate, interrupting all builds running on …

CVE-2026-109251